<VV> original GM Corvair Lifters - resurfacing

[Tony Underwood]

At 12:02 AM 2/20/2011, Mark Durham wrote:
>Tony, once the lifter base has been resurfaced, its like a new lifter,
>so there isn't a mismatch pattern that can take out the cam. Like
>rings, they "wear in" to the cam and as long as that happens in a good
>way they should last a long time.


Goes without saying.  :)


>But as a lifter wears, so does the
>cam and older cams may have lost their correct profile and may quit
>turning the lifter on each lift cycle, A line forms, and the lifter
>and cam quickly wear from there.


If the cam is worn that bad and won't spin the lifter, it's unlikely 
any lifter is going to work out for any great length of time.

The point of refacing a lifter is to save a still-functional camshaft.


>Another consideration is the reduced lenght with a lifter that has
>been resurfaced.

Nope, NOT a consideration at all.   If you have to remove enough 
metal from the face of that lifter to affect valve geometry, THAT 
lifter is long since shot to Hell.

Refacing a lifter means you take off only enough to remove the polish 
and insure the face is linear across its dimension.  If you have to 
take off as much as, for instance ~.003, that's too much, IMHO.  You 
can tell the difference easily once the lifter face is lapped... just 
by checking it occasionally, which you should be doing constantly in 
the first place.


>It will change valve train geometry so when you put
>that back together check the geometry.


A lifter that's around .003 shorter than it used to be is not going 
to have an affect on valve geometry.   If you dismantle most engines 
made in that era and measure tolerances, I'm willing to bet that 
you'll find wider variations than that in NEW stuff... and they all 
seemed to work out pretty well.  Besides:

Take a look at the tips of the valve stems.   Then the rockers.  AND 
the rocker balls.  Look at the wear on the contact surfaces.  There's 
a lot of engines out there running just fine with MUCH more wear on 
valve stems and rocker faces than you'd EVER take off a still-useable 
lifter face to clean it up.  Tolerances widen and loosen in lots of 
places along the way... and sometimes those odd tolerances were there 
from the beginning.


My favorite was a V8 block that originally came out of Dearborn that 
was sent to the machine shop for freshening up during a rebuild which 
had a FACTORY deck height variation on ONE bank (just one, the other 
bank was fine) from front to rear of...  (wait for it)  -=[ .102" ]=- 
and before the rebuild it had run pretty well for all of its 30+ 
years.   I'd been curious about how well its intake had sealed but 
evidently there hadn't been any issues.   All it was doing wrong was 
smoking a bit, still had been running fairly well before the rebuild.


>You may have to get longer push
>rods so the rocker pushes straight down on the valve stem.


Again, if the lifter was THAT worn so as to throw the geometry off, 
it went into the trash.   And it would have had to be pretty worn to 
cause that kind of trouble... enough that refacing it wouldn't help 
anything.   Again, common sense dictated the terms.




tony..